Does keto diet improve performance?

Like many of my fellow athletes I too look for ways to improve my performance. For the last two years the hot topic of keto (short for ketogenic) diet keeps on popping up sparking endless debates... The allure of losing weight by switching your body from primarily burning carbohydrates to burning fat for fuel seems like a holy grail especially for endurance athletes. Your body naturally stores tens of thousands of calories in the form of fat, ready to be used for energy. No longer do you need to rely on replenishing your depleted glycogen reserves with carbohydrates such as gels, energy bars etc during your workouts and races, just burn away all the fat you are already carrying on you. That all just sounds so amazing! So, what's the catch?

This could be yet another fad diet or a true life-changer. So what does the science say? Well, according to the article in the Popular Science: Sorry, keto fans, you're probably not in ketosis it is extremely hard to get your body into a true ketosis state and the side-effects can compromise your long-term health. However, ketogenic diet has been successfully used since 1920s for treatment of epilepsy in children.

What about the performance benefits? After all some athletes don't mind getting an extra edge at any cost. This is one of many interesting topics that Alex Hutchinson (a competitive athlete and an editor for Outside Magazine) discusses in his wonderful book: Endure, Mind, Body and the Curiously Elastic Limits of Human Performance. After doing his research on the subject he comes to a conclusion that for a low intensity endurance like hiking, the ketogenic diet may work. However, for competitive endurance training and racing the science shows no benefits and as the intensity of the effort increases, it actually shows a decline in performance.

These are the main takeaways for me on a keto diet. I haven't tried it, have you?

Joking aside, I think Keto makes sense in isolation, if you think about the demands of an extreme duration sport like Iron Man, or Ultrarunning, double Century. Where there is no top end required, just a constant low hum of energy.

The problem is that if you go full Keto, which takes a long time, then you can't train effectively. In order to raise sustained power output, you have to do high intensity work to get things working more efficiently. So overall I suspect you would end up with a lower power output.

I have genetically high cholesterol and tried the Paleo diet for a year. I felt pretty good and lost some weight—probably from eliminating pastries—but at the end of the year my cholesterol was still 230. I tried statins but I'm one of the small percentage of people who doesn't tolerate them well.

From a tip on Slowtwitch, the triathlon forum, I got deep in the books and research about plant-based diets where the fiber is left in tact. So brown rice, not white, apples, not apple juice, veggies, beans... It only took 2 weeks to get my cholesterol to 170. I lost more weight, recovered from workouts better, and felt better. Shocking, yes, but it turns out it was well known by food researchers, just not me.

Three doctors I know, my wife, and perhaps a dozen of our friends watched the transformation and followed suit. One of the docs, my personal physician Dr. Souvignier, who once packed some pounds, now teaches a 6-workshop series at Sutter Health about it. He looks physically transformed. One of our friends had severe Type II diabetes and was on the keto diet for years in an attempt to control her blood sugar. She tried going all whole plants and was off her insulin within about 30 days. She even wrote .a paper about it in a diabetes academic journal. Turns out her story isn't very unique.

You've brought up an interesting point about ultra events (extreme duration) like Ironman 140.6 or a Double Century (200 mile bike ride). In theory these are the perfect candidates to prove the benefits of Keto diet. I'd love to hear from somebody who's done one while on a keto diet. Even better would be to compare the same or similar races before and after starting the diet.

Zach Bitter is the poster boy of keto in the ultra community and he's been pretty speedy even in shorter races like the Comrades Marathon in Africa (56 miles). He placed 32nd there in a world-class field and averaged a little less than 6:30/mile. It's hilly too.

And he's the American record holder for 100 miles on the track. He was able to average 7 minutes/mile for the whole thing. The thing is fat has a lot of calories and it doesn't upset your stomach so you don't have to eat much. The women's winner of the grueling Western States 100 last year ate cake frosting the whole way. Lots of fat with an immediate kick from the sugar.

I won't go full Keto, mostly because I just don't have the motivation and/or time to strictly adhere to such a lifestyle change. I am on the intermittent fasting program though and am liking its benefits thus far. I do a FDF (Full Day Fast) one day per week, typically Monday which is my rest day from training.

Beginning Sunday evening about 9-10pm, I'll have nothing but high ph water with added drops of trace minerals per quart bottle. I'll go through 1-1.5 gals of water in that 24 hour period, then break the fast with some bone broth, 1/2 an avocado, and maybe some nuts or a boiled egg.

I still eat within healthy limits for the remainder of the week, but don't worry as much about ingesting carbs when desired or necessary. Lots of whole foods, brown rice, meats when desired, etc... I'm cognizant of how much alcohol I consume, and sweets as well. I've found a balance that works for me and I'll alter the density/quantity of my calories based on my training load and upcoming race(s).

Each person will react to certain foods and nutritonal shifts differently so anything new, such as Keto or Intermittent Fasting, needs to be done with patience, a log of perceived effects, and finding your own personal balance along the way. If you have a doctor monitoring blood work along the way, all the better.

There has been a belief among elites for a very long time that it hurts their performance if they go too long between meals or get too hungry. Runner's World had an interesting article about Meb Keflezighi trained to win the Boston Marathon at his decrepit olde age where he said 5 small meals spaced throughout the day.

Mark Allen, the 6-time IronMan World Champion and coach who helped Chris McCormack win three of them, said it's all about training heavy and racing light. In other words, drop the weight once a year for your A race in the weeks preceding the race when you're tapering, but for the other 11 months don't go hungry, it slows recovery.

My adherence to the intermittent fasting program is working well for me. Mondays are always a rest day, and I'm usually in front of the computer all day anyway as well, trying to catch up on weekend emails. I've lost about 4 pounds since starting the plan and, though hard to articulate; I feel more cognitively aware and clear of mind. A feeling of clarity to my mind usually comes on about mid-afternoon on my fast day and, though odd, it's welcomed.

I raced #9 of my regional XC series yesterday and placed 2nd on a semi-flat rear tire. Still leading in points for the singlespeed category over the 10 race series. Last race is in two weeks.

Awesome, Ridge. I forgot to mention when I spoke of Meb Keflezighi, he had a training theory that you should be a little bit depleted on long workouts to simulate race day when you have to burn fat at the end of a long race. Get the body used to it. When he says long, he means 2 hours 10 minutes. For some cyclists and ultra runners, that can mean short.

I have a friend who was very interested in this diet and he has a background as an extremely competitive science. He got me very curious about it and my quick study of it suggested to me that there was no serious scientific evidence to support the notion that ketonic diet worked for a competitive endurance athlete. That's not to say that at some point there may be some evidence to show that it can indeed work for some people. At this point I think it would hinder an athlete's performance by not giving them the calories or fuel they need to perform the arduous training required to compete at a high level in these sports. Anyone interested in this diet needs to remind themselves or rather keep asking themselves "What evidence would it take to convince me that ketonic diet is NOT effective?". This way the person won't fall into the trap of convincing themselves it is true or will work. This could happen because they may start reading lots of articles, research or anecdotal stuff by people who are convinced that it works or should work when in fact the science isn't currently showing that is is effective. Time will tell.

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